1. Field of the Invention
The present invention relates to a vehicle suspension system, and more specifically, to a rear suspension system for a motor vehicle.
2. Description of the Prior Art
Conventionally, known vehicle rear suspension systems, as those shown in U.S. Pat. Nos. 4,754,992 and 4,690,426, comprise a wheel carrying member for rotatably carrying a vehicle wheel, three lateral links extending outwardly in a transverse direction of a vehicle body and connected to the wheel carrying member at the outer ends thereof, and a trailing arm or longitudinal member extending in a longitudinal direction of the vehicle body and connected to the wheel carrying member at a rear end thereof so as to control a toe angle and a camber angle of the wheel when the wheel is bumped to move upward relative to the vehicle body and rebounded to move downward relative to the vehicle body during running of the vehicle.
In order to control the toe angle of the wheel, Japanese Utility Model Public Disclosure No. 61-59107, laid open to the public in 1986, discloses a rear suspension in which the trailing arm is swingably connected with the wheel carrying member at a rear end about an axis extending in an up and down direction while a relative movement between the trailing arm and the wheel carrying member along the axis is restricted.
With this suspension system, the trailing arm is constituted by a pair of links spaced from each other in the up and down direction or a plate member having a large enough dimension in the up and down direction and connected with the wheel carrying member at the rear end through at least two points spaced in the up and down direction for supporting the wheel carrying member with regard, particularly, to a moment acting on the wheel carrying member about a wheel axis as well as a longitudinal force acting on thereon through the wheel. As aforementioned, the three lateral links are also connected with the wheel carrying member, respectively. It may be difficult, therefore, to connect all such members to the wheel carrying member in a desirable arrangement. In a case where the trailing arm is constituted by a pair of links, it is desirable to provide a rubber disposed at a connecting point between the link and the wheel carrying member with a soft resilient property from a point of riding comfort. However, such soft resilience may cause a problem such as a brake judder.
Japanese Patent Public Disclosure No. 60-61318, laid open to the public on Apr. 9, 1985, discloses a rear suspension provided with a trailing arm and three lateral links, wherein the trailing arm, extending longitudinally, is connected with the wheel carrying member at a rear end, and one of the three lateral links is connected with the trailing arm through another link. This structure, disclosed in the Japanese Patent Public Disclosure No. 60-61318, is advantageous in that the number of connecting point at the wheel carrying member can be reduced, and brake judder can be prevented. An improvement in riding comfort is also provided.
It should, however, be noted that the suspension of the Japanese Patent Public Disclosure No. 60-61318 is disadvantageous in controllability of a wheel attitude, since the wheel tends to produce a toe-out movement.